A.B.
I honestly think all this prenatal testing and technology can do more harm than good. In all likelihood everything is fine. I say that because the dr. said they are only "slightly" enlarged. So it is probably just a variation of normal. Now that they can "see" so much more due to technology, it has just opened up endless possibilities of things to freak out about when most of the time everything is fine. For example, during my ultrasound i was told I have a misshapen uterus and that it might cause problems. I went on to deliver a perfectly healthy baby and if it were the 1850's i probably would have gone on to deliver 10 more without any doctor ever realizing my uterus is not the "right" shape.
Oh and not to sound TOO cynical but another thing to keep in mind, the doctors love all these tests, procedures and office visits because that is how they make money. I'm not saying they are evil, just that that is how their system works. They will offer you every test and procedure under the sun because that is how they do things. But it is not always necessarily in your best interest.
Finally....even if your baby does have an abnormality, you will LOVE him or her with all your heart once they are born.
Best wishes to you!